'The end of the human race'. On the list of doomsday scenarios that could wipe out the human race, super-smart killer robots rate pretty high in the public consciousness.
All stars live by fusing hydrogen into helium. In the first step of the process, two hydrogen atoms fuse to form deuterium. In the next step, another hydrogen atom fuses with the deuterium, creating a rare isotope of helium that has two protons and one neutron in its nucleus. In the third step, two of the rare helium atoms fuse to create a single normal helium atom and two hydrogen atoms. The fusion pathway described above requires six hydrogen atoms to create one helium atomâhowever, there are two hydrogen atoms left over at the end of the process. The net result is that it takes four hydrogen atoms to make one helium atom.
Once all of the hydrogen in a gas is converted into helium-4, fusion stops until the temperature rises to about 10 8 Â°K. At this temperature, helium-4 is converted into heavier elements, predominantly carbon-12 and oxygen.-16, both of which are multiples of helium-4 in their proton and neutron composition.. C 12 + Î³. The process of converting three helium-4 nuclei into a single carbon-12 nucleus releases a total of 7.27 MeV, all of which remains trapped within the star. This fusion chain can be treated as a single process; it is then called the triple-alpha process (an alpha particle is a helium-4 nucleus).